Engine fuel test device



Oct. 23, 1962 Fuel G. H. MEGUERIAN ETAL ENGINE FUEL TEST DEVICE Filed 001;. 22, 1959 INVENTORS y 7/ E Rupe/ ATTORNEY United States Patent s,ssa,4s7 ENGENE FUEL TEST DEVICE Gar-bis H. Meguerian, Park Forest, 111., and William F.

Rumpel, Denver, Colo, assignors to Standard Oil Company, Chicago, ILL, a corporation of lndiana Filed Oct. 22, 15,Ser.No. 848,151 6 Claims. (Cl. 73-61) This invention relates to a laboratory apparatus for testing fuel compositions for use in internal combustion engines. This invention further relates to an englne fuel test device for giving indications of deposit forming and removing properties of fuel compositions which indications may be correlated with deposit forming and removing properties of the sample as a fuel in an operating internal combustion engine.

In the development of new fuel compositions by blending as well as by formulating with addition agents, gum and varnish deposition and particularly deposits on the intake valves of the engine under conditions of operations are a major concern. It is desirable to formulate englne fuel compositions so that they will function without leaving such deposits and sometimes with the additional ability to remove deposits which have already been formed within the engine. Any proposed new fuel composition produced in the laboratory must be extensively tested before it may be used as a commercial engine fuel. Laboratory tests, although they are helpful and enable the researcher to foresee certain deposit forming tendencies of engine fuel, are generally not entirely reliable; many of the test procedures do not give results which are correlated with results under engine operation. After passing the laboratory tests, proposed fuel compositions are then subjected to expensive and time consuming engine tests which are actually conducted in an internal combustion engine under operating conditions. Some such engine tests take up to a week or more to run and because of the limited number of engines available for engine tests it is desirable to screen out as many proposed fuel compositions as possible by a laboratory technique or with a laboratory device.

This invention provides an engine fuel test device which gives results with regard to gum forming and removing properties of a fuel, which results are correlated with results obtained in an operating internal combustion engine. The device of this invention may be used in a technique for determining deposit forming and removing properties of fuels in a minimum of time and with little fuel expenditure. The device is particularly useful in screening samples of fuel compositions in a laboratory, thereby eliminating many of the actual engine tests necessary during development of a fuel having a minimum of deposit removing properties or having some deposit removing ability.

The device of this invention provides a heated conduit which is removable from the heating source and is interchangeable With other conduits. The conduit is positioned at an inclined angle to provide gravity flow therethrough from an upper end to a lower end. The heating source is capable of providing preselected temperatures within the range of from about 100 to about 450 F. and preferably a gradient of temperatures within that range. The conduit is provided with fuel and air inlet means at the upper end and outlet means at the lower end. As a technique for determining deposit forming or removing properties of a fuel composition the conduit is heated to a preselected temperature and fuel and air are introduced at the inlet and flowed by gravity through the conduit. The deposits formed in or removed from the conduit are then measured and the measurement is taken as an indication of the fuel composition properties. The

2 conduit may then be prepared for another test run such as by cleaning, or may be replaced by another conduit FIGURE 1 illustrates an embodiment of the engine fuel test device of this invention.

FIGURE 2 illustrates a second embodiment of the engine fuel test deviceof this invention.

With reference to FIGURE 1 and the embodiment illustrated therein, conduit 1 is provided in chamber 2 of heating means 3. Conduit 1 is elongated and of such configuration so as to provide substantial lateral and bottom confinement of a fluid engine fuel flowing from end to end therethrough. Although conduit 1 is prefera-bly an elongated tube conduit 1 may advantageously be an elongated trough, such as, for example as is shown in FIGURE 2 as conduit 20, configurated and positioned so as to give said substantial lateral and bottom confinement. Conduit 1 is preferably essentially straight to allow free flow of an engine fuel fluid therethrough without permitting appreciable amounts of the fluid to collect at any point along the conduit. The conduit is readily removable from chamber 2 and heating means 3 and is interchangeable with other conduits. For any series of tests of a fuel or fuels, the same configuration of conduit 1 must be used. Conduit 1 is constructed of a solid material which is heatable within the range of from about F. to about 450 'F., such as, for example, glass, carbon steel, stainless steel, other alloy steels, galvanized steel, brass, copper, silver, aluminum, Bakelite, and the like. Where conduit 1 is a tube, glass is a preferred material since it allows visual observation of the deposits as to their position and nature within the tube. Conduits of different materials may be provided and may be interchangeable for alternating use, for example in order t determine the effects of such different materials on gum deposition. Conduit 1 is fitted within the chamber of heating means 3 with sufficiently snug fitting to retard its longitudinal gravitational movement from chamber 2 and is thereby held in heatable association with heating means 3 during use. The conduit may be removed from the chamber by rotatably and/ or longitudinally moving the conduit with an applied force to extract the conduit. Alternatively, the conduit may be provided with lugs, clamps, splines, or other aflixing means for afiixing it in heatable association with the heating means. In all cases, however, the conduit is removable from the heating means.

Chamber 2 within heating means 3-is an elongated chamber through heating means 3 and is adapted to receive conduit 1 as hereinabove described. Chamber 2 may be an elongated tube, such as for example a metal tube, in which conduit 1 is snug fitted such as illustrated in FIGURE 1, or chamber 2 may simply be a passageway or space provided within heating means 3 or constructed as a part of heating means 3. Chamber 2 is in any event advantageously provided with means for assuring the snug fit of conduit 1 therein, such as is provided by the elongated tubular configuration of chamber 2 as illustrated in FIGURE 1 or as may be provided by finger projections, ribs or rings Within chamber 2 at various positions along chamber 2, such as for example at each end of chamber 2.

In order that the conduit may be readily removed from chamber 2 and heating means 3, the conduit is advantageously rotatably and longitudinally positioned within chamber 2. Conduit 1 is mounted on a slope by mount ing means, such as inclined stand 4, to provide gravity flow therethrough. The illustrated slope is about 15 although it is to be understood that any slope can be used as will provide adequate flow. Inclined stand 4 is provided with curved surface 5 which is configurated to receive heating means 3. The mounting means may be any such means known to the art such as, for example,

an assembly of clamps and bar stands as are used to position condensers and the like, a sling arrangement, an inclined surface, a supporting block, etc. The mounting means may advantageously be adjustable to provide a number of differing degrees of slope or inclination in order to regulate gravity flow rate through and fluid residence time within conduit 1. Conduit 1 is thus positioned on an inclination providing an upper inlet end 6 and a lower outlet end 7. Inlet end 6 of conduit 1 is provided with fuel inlet 8 and air inlet 9. Fuel inlet 8 is advantageously provided with fuel flow meter means such as fuel flow meter 10 and air inlet 9 is advantageously provided with air flow meter means such as air flow meter 11.

Heating means 3 may be any furnace-type heating means. For control purposes, heating means 3 is advantageously electrically operated such as by electrical heating coil 12. Heating means 3 should be adequately insulated to provide a constant preselected temperature or temperature gradient within chamber 2 and conduit 1. The temperature provided by heating means 3 is controlled by a temperature controller 13 and the temperature within chamber 2 is recorded by temperature recorder 14 responsive to a temperature sensing means such as thermocouple 15 positioned within chamber 2 preferably at either the inlet or outlet end of chamber 2. Heating means '3 is conveniently provided with insulation jacket 16 to conserve heat and protect personnel from burns.

When testing engine fuels for deposit forming tendencies the conduit should be substantially clean at the start of the test. When testing engine fuels for deposit removing tendencies or solvency action, the conduit should have coated on its interior such gum or deposits as an engine normally contains. A conduit having an inner surface coated with gum or deposits may advantageously be obtained by flowing a known gum pro ducing engine fuel through the test device according to the test procedure outlined below.

In operation, fuel and air are flowed through inlets 8 and 9 into conduit 1. The fuel and air should be metered to provide a weight ratio of fuel to air and from about 3:1 to about 1:1. Heating means 3 is activated by temperature controller 13 to produce a temperature in the range of from about 100 to about 450 F. within chamber 2 and conduit 1. Heating means 3 may be such that it is capable of providing a temperature gradient of 100 F. within said range. The temperature gradient may be provided by incrementally changing the temperature over a period of time where temperature controller 13 is a timer mechanism which intermittently or continually increases or decreases the temperature provided within chamber 2 and conduit 1. Heating coil 12 is included in heating means 3. Preferably a gradient temperature from one end of chamber 2 and conduit 1 to the other end of chamber 2 and conduit 1 may be provided by a heating coil such as heating coil 12, by employing a heating coil having a gradient in numbers of coil loops along its length or in thickness of Wire over the length of heating means 3; such expedients are conventionally used by those skilled in the art to provide temperature gradients. Where the gradient temperature is provided over the length of the chamber and conduit, the lower temperatures are at the inlet end of conduit 1 and the higher temperatures are at the outlet end. The fuel and air should be allowed to flow through conduit 1 and out of outlet 7 for a period of time of from about 60 to about 200 minutes. The rate of flow of fuel should be from about one to about three ml. per minute and the rate of flow of the air should be from about 200 to about 1000 ml. per second. Temperature recorder 14 responsive to thermocouple 15 is activated and records the temperature within heated conduit 1 during the flow of fuel and air.

Conduit 1 may be weighed before and after the above A. operation and the difference in weight is taken as the amount of deposits formed or removed during the operation. Other known method of measuring the deposits may also be used.

In another embodiment, not illustrated, the conduit is constructed of an electrically non-conducting material and is provided with an electrical conduit strip positioned lengthwise within the conduit and the lower inside surface of the conduit. During operation of the device the deposits will tend to form on the conductive strip and the change in resistance due to cooling of the strip by deposit formation can be taken as a measure of deposits formed.

With reference to FIGURE 2, heating means 21 is constructed of an electrically conductive material and is provided with conduit 20 which is an elongated trough as described above positioned in chamber 22 running lengthwise through heating means 21 and having inlet means 2'3 and outlet means 24. Conduit 20 may also be an elongated tube such as shown in FIGURE 1 and described above. Heating means 21 is of decreasing diameter from the inlet end to the outlet end and is heated by electrical resistance means by charging a current through leads 25' and 26. The difference in diameter along heating means 21 alters the resistance of heating means 21 to provide a lower temperature at inlet 23 where heating means 21 is of larger diameter and a higher temperature at outlet 24 where heating means 21 is of smaller diameter. Heating means 21 should be configurated so as to provide a temperature gradient of from about 50 F. to about 150 F. within conduit 20 and chamber 22, and prefer-ably of about F. Temperature controller 27 maintains the temperature gradient within the range of from about 100 F. to about 450 F. The temperature is recorded by a temperature recorder such as resistance temperature recorder 28 which measures the change in electrical resistance of heating means 21.

Conduit 20 is held on a slant to allow gravity flow therethrough by electrically insulated clamp 30 aflixed to and grasping heating means 21. Clamp 30 is supported by stand 31 through conventional attaching means. Gravitational flow is from conduit inlet 23 to conduit outlet 24. In operation, a test engine fuel is metered by fuel flow meter 32 and introduced into conduit 20 at conduit inlet 23 via fuel inlet 33 and an oxygen containing gas, such as air, is metered by air flow meter 34 and introduced in to conduit 20 at conduit inlet 23 via air inlet 35. Conduit 20 is maintained at temperature gradient as hereinabove set out and engine fuel and air are continually supplied at conduit inlet 23 in a predetermined ratio. At the end of the test period, the conduit is weighed and the difference in weight after the test, with reference to weight before the test, is a determination of the amount of deposits formed or removed during the test. The conduit may be washed with various solvents to determine the various types of deposits formed or removed and the conduit may be weighed between solvent washings to determine the amounts of the various types of deposits. The amounts of deposits are an indication of deposit forming or removing properties of the test fuel and may readily be correlated with results obtained in engine tests. With reference again to FIGURE 1, conduit 1, an elongated tube, is illustrated as advantageously provided with a projection or lip such as flange 29 for rotationally and longitudinally moving conduit 1 Within chamber 2 in heating means 3 and for removing conduit 1 from chamber 2.

To demonstrate the correlation of the results obtained by using the present apparatus with engine test results, various fuel compositions containing different addition agents in amounts set out in the table below were tested with the results shown in the table by three test procedures, two of which are engine tests and the third of 5 which was a procedure using the apparatus of this invention. The tests used were as follows:

Lauson Engine Test The Lauson engine tests were run in accordance with a procedure described in a paper entitled: Evaluating 6 fuel composition are indicated in the table as a ratio load of the tetraethyllead to phosphorus of the addition agent. Amounts of addition agents in fuel compositions 4-6 are expressed in pounds per 1,000 barrels. The results of the above three test procedures are reported in the table below:

TABLE Additive Lauson Triple Eng. Test Chevrolet Temp. Rate of Total Hexane Solvent Acetone ISD of Con- Fuel Rate of Air Deposits, Soluble Soluble lb./l,000 PzPb Soluble Test duit, F. Flow, Flow, cc./min. mg. Deposits, Deposits, No. bls. Ratio Deposits, mL/hr mg. mg.

fail 150 50 Uneontrolled- 59.3 fall 150 50 d 66. 5 pass 150 50 5.4 pass 150 50 7.3 pass 150 50 5. 6 pass--- 150 50 6.0 pass 150 50 -6 80.2 pass 280 60 24.5 267.4 fail 280 60 36.4 68.8 pass 280 60 14.3

1 Five runs were made with the same additive to determine the variance between results.

Gasolines for Induction System Gums by C. C. Moore, J. L. Keller, W. C. Kent and F. S. Liggett, presented before the SAE National Fuels and Lubricants Meeting in Tulsa, Oklahoma, held November 4-5, 1954 (available as Preprint No. 406 from the SAE Special Publications Department).

Chevrolet ISD Test In the procedure of this test, the various fuel compositions were used as engine fuels in a straight six cylin der Chevrolet engine having a compression ratio of 7:1. Each sample was run at 2500 rpm. for 50 hours. At the end of the 50 hour run, the compression of the engine was checked to determine valve dragging or sticking stems. The engine fuels were rated \by a schedule based on the effect of gum and deposits on valve dragging and sticking stems. The rating schedule is as follows:

Result: Rating No valves dragging or sticking stems Pass. One valve dragging Border line, fail. No sticking stem Fail. More than one valve dragging or sticking stem Fail.

Present Device Test Procedure The apparatus used in this test procedure was a resistance furnace consisting of an insulated heating element Wrapped around an 18 length of glass tubing having l /s" internal diameter. The resistance furnace had a removea-ble stainless steel trough as a conduit placed within the glass tubing. A Variac was used to maintain the proper temperature in the trough and temperature measurements were made with thermocouples placed along the steel trough. 100 ml. samples of the fuel compositions tested were allowed to fiow through the furnace at the temperatures indicated in the table and at the rate of flow indicated in the table. The rate of air flow on some samples was uncontrolled and on other samples was controlled as indicated in the table. The trough was removed after each sample and the total weight of deposits formed was determined by the difference in weight of the trough from the weight of the trough plus deposits. In some runs as indicated in the table hexane soluble deposits and triple solvent soluble deposits were also determined by solvent washing. The triple solvent used as a mixture of methanol, chloroform, and acetone.

The above three test procedures were run on leaded gasoline compositions (3 ccs. of commercial tetraethyllead fluid) containing various addition agents. The addition agents of fuel compositions 1 through 3 were of the phosphorus-amine type and the amounts used in each A few runs on various addition agents at various temperatures with both the present device and a reliable engine test give a correlation of readings which may be used to determine an optimum operation temperature for a particular test instrument of the type herein disclosed. Once the correlation has been established, the device may then be used to determine deposit forming and removing tendencies of a fuel composition. It can be seen from the data of the table above that for the particular device used in the test procedure a fuel depositing only 24.5 mg. per cc. in the present device passed the Chevrolet ISD Test and also gave good results in the Lauson Engine Test while a fuel composition depositing 36.4 mg. per 100 cc. failed the Chevrolet ISD Test and gave extremely poor results in the Lauson Engine Test. Other runs may be made to determine a more exact pass or fail division correlation between the device and engine tests if desired.

It is evident from the above that we have provided a new device and testing procedure for determining the deposit forming and removing properties of engine fuel compositions whereby the results obtained may be correlated with results obtained in operating internal combustion engines.

We claim:

1. An apparatus for ascertaining gum and deposit forming and removing properties of an engine fuel composition which apparatus comprises an elongated sloping heatable conduit having an inner surface, an upper end and a lower end, inlet means at said upper end and outlet means at said lower end providing gravity flow of a fluid engine fuel composition through the length of said conduit, heating means for heating said conduit at a preselected temperature, said conduit being removable with respect to said heating means, temperature sensing means for sensing the temperature of said inner surface, temperature control means responsive to said temperature sensing means for controlling the temperature of said inner surface, and means for removing said conduit from said heating means.

2. An engine fuel test device for indicating gum and deposit forming and removing properties of an engine fuel which device comprises a jacket heating means having an elongated chamber, a heatable elongated oonduit carried within said chamber by said heating means and longitudinally and rotatably moveable within and removable from said chamber, inlet means at a first of said conduit for charging fluid engine fuel and oxygen-containing gas to said conduit, means for metering the flow of engine fuel and oxygen-containing gas to said conduit, outlet means at a second end of said conduit, mean for positioning said conduit on a slope whereby longitudinal gravity flow is provided from said inlet means to said outlet means, an inner surface within said conduit and capable of collecting gums and deposits, temperature sensing means for sensing the temperature of said inner surface, temperature control means responsive to said temperature sensing means for controlling the temperature of said inner surface at a pre-selected temperature gradient of at least about 50 F. within the range of from about 100 F. to about 450 F, and means for removing said conduit from said chamber for inspection and measurement of gum and deposits on said inner surface as an indication of gum and deposit properties correlated with the gum and deposit forming and removing tendencies of said engine fuel in an operating internal combustion engine.

3. The engine fuel test device of claim 2 wherein said temperature gradient is a longitudinal gradient on said inner surface within said conduit.

4. The engine fuel test device of claim 2 wherein said temperature gradient is an intermittently changing uniform temperature at said inner surface.

5. An apparatus for ascertaining gum and deposit forming and removing properties of an engine fuel composition which apparatus comprises an electrically conductive heating jacket capable of providing temperatures in the range of from about 100 F. to about 450 F., an elongated heatable conduit carried Within said heating jacket, inlet means at a first end of said conduit for charging fluid engine fuel and oxygen-containing gas into said conduit, means for metering the flow of engine fuel and oxygencontaining gas into said conduit, outlet means at a second end of said conduit, means for positioning said conduit on a slope whereby longitudinal gravity flow is obtainable within said conduit from said inlet means to said outlet means, an inner surface within said conduit and capable of collecting gums and deposits, lead wires attached to said jacket adjacent each end of said jacket for charging an electrical current to said jacket, temperature sensing means for sensing the temperature of said inner surface, temperature control means responsive to said temperature sensing means for controlling the temperature of said inner surface by regulating the electrical current charged to said jacket, and means for removing said conduit from said jacket.

6. Au engine fuel test device for ascertaining gum and deposit forming and removing properties of a fuel composition, which device comprises a heatable conduit removeably positioned on an inclined slant in heat receiving proximity to a heating source, inlet means at an upper end of said conduit, outlet means at a lower end of said conduit, means for controlling the temperature of the inner surface of said conduit within the range of from about F. to about 450 F. and means for causing fluid flow of a fuel composition from said inlet means to said outlet means.

References Cited in the file of this patent UNITED STATES PATENTS 1,554,993 Ettele Sept. 29, 1925 2,500,964 Sullivan et al Mar. 21, 1950 2,746,285 Greania May 22, 1956 

